IStream::Seek
Changes the
seek pointer to a new location relative to the beginning of the stream, to the
end of the stream, or to the current seek pointer.
HRESULT Seek(
|
LARGE_INTEGER dlibMove, |
//Offset
relative to dwOrigin |
|
DWORD dwOrigin, |
//Specifies
the origin for the offset |
|
ULARGE_INTEGER * plibNewPosition |
//Pointer
to location containing new seek pointer |
|
); |
|
Parameters
dlibMove
[in]
Displacement to be added to the location indicated by dwOrigin. If dwOrigin
is STREAM_SEEK_SET, this is interpreted as an unsigned value rather than
signed.
dwOrigin
[in]
Specifies the origin for the displacement specified in dlibMove. The
origin can be the beginning of the file, the current seek pointer, or the end
of the file. See the STREAM_SEEK enumeration for the values.
plibNewPosition
[out] Pointer
to the location where this method writes the value of the new seek pointer from
the beginning of the stream. You can set this pointer to NULL to indicate that
you are not interested in this value. In this case, this method does not
provide the new seek pointer.
Return Values
S_OK
The seek
pointer has been successfully adjusted.
E_PENDING
Asynchronous
Storage only: Part or all of the stream s
data is currently unavailable. For more information see IFillLockBytes and Asynchronous
Storage.
STG_E_INVALIDPOINTER
The value of
the plibNewPosition parameter is not valid.
STG_E_INVALIDFUNCTION
The value of
the dwOrigin parameter is not valid.
STG_E_REVERTED
The object
has been invalidated by a revert operation above it in the transaction tree.
Remarks
IStream::Seek changes the seek pointer so subsequent reads and
writes can take place at a different location in the stream object. It is an
error to seek before the beginning of the stream. It is not, however, an error
to seek past the end of the stream. Seeking past the end of the stream is
useful for subsequent writes, as the stream will at that time be extended to
the seek position immediately before the write is done.
You can also
use this method to obtain the current value of the seek pointer by calling this
method with the dwOrigin parameter set to STREAM_SEEK_CUR and the dlibMove
parameter set to 0 so the seek pointer is not changed. The current seek pointer
is returned in the plibNewPosition parameter.
See Also
IStream
- Compound File Implementation, STREAM_SEEK, IStream::Read, IStream::Write